1. Technical Field of the Invention
The present invention generally relates to a connecting structure for battery terminals and, more particularly, to a connecting structure for surely connecting battery terminals to battery electrodes of corresponding polarity of a battery body mounted on a vehicle without miscontact of the battery terminals with the battery electrode.
2. Related Art
FIGS. 4 and 5 illustrate a related connecting structure for fastening and fixing battery terminals, provided at an end of an electric wire connected to various kinds of electrical equipment, to battery electrodes of a battery body, mounted on a vehicle, by screw members.
This connecting structure for a battery terminal is disclosed in JP-A-4-220947, and configured so that a positive battery electrode 3 and a negative battery electrode 4 of the vehicle-mounted battery body 1 are quadrangular-prism-like posts 3b and 4b respectively erected on base potions 3a and 4a on the top surface of the battery body 1.
Each of the posts 3b and 4b has a flat abutting surface 6 or 7 formed at the tip thereof. In each of abutting surface portions 6 and 7, a screw hole 8 or 9 for securing a battery terminal 11 or 12 (to be described later) by screws is formed. These screw holes 8 and 9 are provided so that the central axes thereof are eccentric from the central portions of the abutting surfaces in different directions in such a way as to make the position of the central axis of the positive electrode with respect to the center of the corresponding screw hole differ from that of the central axis of the negative electrode with respect to the center of the other screw hole.
Each of the battery terminals 11 and 12 includes: a flat plate portion 11a or 12a adapted to abut against a corresponding one of abutting surfaces 6 or 7 respectively formed at the tips of the posts 3b and 4b; an abutting wall portion 11b or 12b which is erected on an edge portion of a corresponding one of these flat plate portions 11a and 12a and abuts against an adjacent side surface of the corresponding post 3b or 4b; and a wire cramping portion 11c or 12c to which a corresponding electric wire 16 or 17 is press-attached.
Further, in each of the flat plate portions 11a and 12a, a screw insertion hole l4 or l5 is provided at an eccentric position corresponding to a corresponding one of the screw holes 8 and 9 respectively formed in the posts 3b and 4b to be connected thereto.
In the aforementioned connecting structure for the battery terminals, the flat plate portions 11a and 12a of the battery terminals 11 and 12 are set on the abutting surfaces 6 and 7 of the posts 3b and 4b so that the screw insertion holes 14 and 15 are aligned with the screw holes 8 and 9 of the posts 3b and 4b. Thus, each of the abutting wall portions 11b and 12b is caught on the corner portion of a corresponding one of the posts 3b and 4b. Consequently, the flat plate portions 11a and 12a serve as rotation inhibiting means.
Therefore, when fastened by bolts 19 screwed into the screw holes 8 and 9, the battery terminals 11 and 12 are restrained from rotating with respect to the posts 3b and 4b. This prevents a direction, in which the wire is drawn, from being changed.
Furthermore, as mentioned previously, the position, at which the screw hole 14 is formed, in the battery terminal 11 corresponding to one of the positive and negative battery electrodes is made to differ from the position, at which the screw hole 15 is formed, in the battery terminal 12 corresponding to the other battery electrode. This prevents each of the battery terminals from being misconnected to the battery electrode of the opposite polarity.
However, although the aforementioned related connecting structure for the battery terminals can prevent each of the battery terminals from being misconnected to the battery electrode of the different polarity, each of the battery electrodes 3 and 4 are exposed to the outside, so that the miscontact of each of the battery terminals 11 and 12 with the battery electrode of the opposite polarity may occur. Thus, there is a fear that electric backflow caused by the miscontact may break the equipment.
Especially, in recent years, there has been a tendency to enhance the efficiency of a vehicle power supply by increasing the voltage thereof. Thus, it is studied to replace 12-volt batteries and 24-volt batteries, which are currently in wide use, with 36-volt batteries. However, the implementation of a high-voltage battery increases the degree of seriousness of the problems of accidents due to the miscontact and sparks due to an arc.
Furthermore, recent increase in the power consumption of per vehicle results in increase in the number of batteries mounted on a vehicle. Thus, there is the need for contrivances to prevent occurrences of a misconnection and a miscontact of battery terminals with a plurality of batteries.
Accordingly, an object of the invention is to solve the problems, and to provide a connecting structure for reliably connecting each of battery terminals with a corresponding one of battery electrodes of a vehicle body without causing the miscontact of the battery terminals with the battery electrodes.
To achieve the foregoing object, according to the invention, there is provided a connecting structure for battery terminals, which is adapted to fasten and fix each of positive and negative battery terminals, which are respectively connected to end portions of wires, to one of battery electrodes, which is of corresponding polarity, of a battery body by screw members. This connecting structure comprises terminal covers, made of an insulating material, for accommodating and holding the battery terminals. Each of the terminal covers comprises a terminal accommodation space having an opening of a predetermined shape that permits only the battery terminal of corresponding polarity to be fitted thereinto. Each of the battery terminals is formed in such a way as to have a shape that permits fitting thereof into a corresponding one of the terminal accommodation spaces. The battery body comprises cover fitting holes of predetermined configurations, each of which permits only the fitting projection pieces of the terminal cover accommodating and holding the battery terminal of corresponding polarity, in the vicinity of each of the battery electrodes so that only the battery terminals are enabled to be placed at a fastening/fixing position on a corresponding one of the battery electrodes, which each of the fitting projection pieces is formed in such a manner as to have a shape enabled to be fitted into a corresponding one of the cover fitting holes.
With the aforementioned configuration, each of the positive and negative terminals respectively connected to the end portions of the wires is electrically connected to the corresponding battery electrode by being placed at a fastening/fixing position on the battery electrode of the corresponding polarity and fastened and fixed by a screw member thereto after the battery terminals are accommodated and held in the terminal covers for respectively accommodating and holding the battery terminals.
Even when the battery terminal is misfitted into the terminal accommodation space of the terminal cover that does not correspond to this battery terminal, this battery terminal cannot be fitted thereinto owing to the difference in the shape therebetween.
Further, even when the terminal cover having accommodated and held the battery terminal is misplaced at the fastening/fixing position on the battery electrode of the polarity that does not correspond to the terminal cover, the fitting projection piece of the terminal cover cannot be fitted to the cover fitting hole of the battery body owing to the difference in the configuration, such as the opening shape and the position, between the fitting projection piece and the fitting hole.
Thus, each of the battery terminals accommodated and held in the terminal accommodation spaces of the terminal covers cannot be placed at the fastening/fixing position on the battery electrode of the polarity that does not correspond thereto. Moreover, even the contact between the battery terminal, which is surrounded by the terminal cover, and the battery electrode of the polarity, which does not correspond to the battery terminal, cannot be achieved.
Therefore, the misconnection between the contact between the battery terminal and the battery electrode, which do not correspond to each other, is known without the contact and electrical conduction therebetween. Therefore, the misconnection therebetween can be reliably prevented.
Further, because the battery terminals are accommodated and held in the terminal accommodation spaces of the terminal covers, arc caused at a moment, at which the battery terminals are in contact with the battery electrodes occurs in the accommodation spaces. Thus, sparks due to the arc do not go out of the terminal covers.
Incidentally, preferably, the temporary latch means for temporarily latching each of the terminal covers at a fastening/fixing position on a corresponding one of the battery electrodes comprises the fitting projection pieces of the terminal covers and the cover fitting holes of the battery body.
Thus, when the terminal covers accommodating and holding the battery terminals are properly set on the battery electrodes, the temporary latch means provided between the fitting projection pieces of the terminal cover and the cover fitting holes of the battery body engage with one another, so that the apparatus is put into a state in which the battery terminals are temporarily fixed to the battery electrodes through the terminal electrodes.
Therefore, one hand of a worker can be prevented from being used for supporting the battery terminals during an operation. of fastening the battery terminals by the nuts. Consequently, the worker can easily perform the screwing operation by freely using both hands.
Furthermore, preferably, each of the battery electrodes comprises a pedestal portion formed in such a way to be projected from the battery body. Moreover, each of the pedestal portions has a predetermined outward form, which permits only the fitting concave portion of the terminal cover accommodating and holding the battery terminal of the corresponding polarity to be fitted thereonto.
Thus, even when each of the terminal covers respectively accommodating and holding the corresponding battery terminals is misplaced at the fastening/fixing positions on one of the battery electrodes, which is of the polarity that does not correspond thereto, the fitting concave portion of this terminal cover cannot be fitted thereonto because of the difference in shape between the corresponding battery electrode and the corresponding pedestal.
That is, in addition to the prevention of the misconnection according to the difference in the distance between the fitting projection pieces of the terminal cover and the cover fitting holes of the battery body, or in the width size of the pieces, the prevention of the misconnection according to the difference in the shape between the pedestal portions of the battery electrodes and the fitting concave portions of the terminal covers can be achieved.
Thus, even when a plurality of batteries are provided in the apparatus, for example, in the case of connecting a plurality of batteries, the misconnection between the battery terminals and the battery electrodes is prevented by suitably changing the shapes, sizes and combinations of such portions to thereby know an occurrence of the misconnection therebetween without the contact and electrical conduction between the battery terminals and the battery electrodes. Consequently, the, misconnection therebetween is reliably prevented.